i bought a semperon 140 today! i have an asus m4n68t-m v2, and had no problem unlocking the 2nd core! amd does not make single core processors since the amd intoduced the semperon 100 series!There are no Dual Core Semprons, they're all single cores since the Athlon XP era.
I would agree on not unlocking it though, Semprons unlock rates are really low, compared to Phenom II unlock rates.